Naniwa S2 Advance Super Stone: 8000 Grit

The Naniwa Advance range, previously called the Super Stone (or SS), excels at various tasks from repairing chips to restoring the original sharpness of edges. Additionally, Naniwa Advance doesn't scratch the sharpening surface, ensuring a mirror polishing result on high end knives and straight razors. Splash-and-go, this stone does not need to be soaked in water before use. Just apply water on the surface and it is ready to sharpen.

These are the S2 series models which are 20mm thick - not 10mm like the S1 series.